Forums/Z31P/z31-repairs-forums engine-mechanical/no spark
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drb5721: (2014-07-13 22:58:15)
This has been asked probably a MILLION times but I have some underlying questions to the possibilities of what may be my problem.
I just got the built engine in along with the hx35, relocation pipe, exhaust, etc. Its ready to start up. Got all starter wiring connected and hit the key. Car turns over til the battery dies. Fuel pump does not prime, but have confirmed good pump. I checked for codes and was getting 11 and 21 and some other codes that are for deleted components. 11 is for the CAS and 21 for the Ignition Signal. I would imagine that with the 21, 11 would be present as well since the CAS is not signaling to fire because there is no ignition prior to?
After getting new dizzy (warranty replacement) and coil (looked original), I played around with it and realized after checking all fuses and relays, the computer lights wouldnt flash anymore. Bypassed the relay by crossing the black and white with the brown at the EFI connector. This got the computer power back. Still not getting spark though. Still getting same codes.
All fuses good, all relays working, have tried 2 stock PTU's as wells as a known working pwr-2. Last option I havent check is the ignition switch. It seems that maybe its getting power to accessories including started but that may be why the ecu lost power and the fuel pump isnt priming. Think it may also be part of the no spark? Is this likely?
Any insight is definitely appreciated.. I am so anxious to hear this thing run. All engine bay grounds are tight. Im at a loss.
G-E: (2014-07-14 00:30:28)
You write much words, yet skip an obvious, please focus on fuel pump circuit for great achievement
drb5721: (2014-07-14 01:35:10)
Fuel pump will not prime and will not pump fuel unless ignition is present though? I MAY be wrong about that. Fuel pump works when bypassing relay. Wiring to pump looks good. Fuse is good. Relay does not click when switching ignition switch or attempting to start. However, the green EFI relay also does not click or allow ecu to power up. Swapped relay with a BLUE one for test purposes since they are the same relay, and no change. Only way I can get power to ECU now is to jump the BROWN and BLACK/WHITE pins in the connector. Seems by the diagram the red wire from that relay to ECU may be suspect?
Or, is ignition dependent on fuel supply? Wiring to fuel pump looks good. Have swapped multiple BLUE relays for circuit to no avail. Fuse IS good. This also makes me think it has
Again, NEW dizzy, NEW coil, wires, plugs, 3 different PTU's, Fuel Pump. No fuel without bypassing connector, and no spark without jumping wires at relay connector.
Not doubting any input, just making sure I am understanding.
dbruce: (2014-07-14 21:22:12)
So is the ECU green lights on? Could also be a bad ignition switch. Check efi fusable link?
drb5721: (2014-07-15 01:11:14)
Ecu does not power up with efi relay in. I have to jump the brown and black wire to get power to the edu. From there I can attempt to start the car but I get no fuel pump prime or spark. Dizzy does not fire injectors when pulled and spun by hand.
drb5721: (2014-07-15 02:20:13)
I am beginning to think it may be related to the ignition switch a little more. As I stated in the first post, is it likely all other electronics would come on and function but only actual starting function be unavailable? I noticed after fumbling around with some things today that when holding the coil wire end and turning the key off and on, I get a SMALL shock come through. Maybe the contacts on the switch are toast? And maybe this is why it doesnt prime the pump when cycling the key or let the injectors fire even when spinning dizzy manually? What gets me is that if the ecu comes on with the wires jumped, from there I would think that should allow power to the other electronics? Maybe the dizzy I have has a bad cas. I have tried a Pathy dizzy that was working at one point as well as a reman warranty replacement.
drb5721: (2014-07-16 01:48:39)
I was able to get the fuel pump to turn ON with key on. It doesnt prime though, just runs. Have new relay coming. Also have another dizzy on the way since I cannot get injector cycling when spinning by hand with key on regardless of relay in socket or wires crossed.
drb5721: (2014-07-18 01:54:46)
Fuel system seems to be working. Pump is turning on. Got ANOTHER dizzy. Still no fire. Swapped efi harness to one the previous car ran with. Still no fire. Guess it might possibly be the harness with the relay box is wired to?
les_joey_paul: (2014-07-18 03:47:48)
Is your ignition control module getting power?
drb5721: (2014-07-18 04:16:36)
Last check yes. Will check again.
drb5721: (2014-07-19 03:31:05)
Icm does not have continuity on pin 2 which is the green wire black trace. I also have no power to 2 pin coil connector…
Pin 3 and pin 5 in 20 pin ecu connector does not show continuity to ground either.
les_joey_paul: (2014-07-19 06:04:45)
Time to prw2 (:
drb5721: (2014-07-19 12:32:11)
PWR2 has been swapped in to test as well. It was also a known working unit. Went back to checking continuity I did actually find that pin 5 has continuity to ground. Pin 3 has none. Pin 3 is also related to ignition circuit. However I am unsure of which harness that wire traces through since it is on the driver side and separate from the EFI harness. These connectors are a part of he harness that runs through the driver fender frame and into the cabin. I guess I will be pulling the harnesses to see where a possible break in a wire is. I also think this may be part of why I am not getting power to the coil.
On another note, I feel I need to pull the engine bay harness to see why I have to jump the brown and black wires at the green efi relay to get power to the ecu. I think the red wire that traces from that relay is broken somewhere which is why the relay is not properly functioning.
Other things I have noticed include that the fuel pump comes on but will not turn off without disconnecting. Interior lights stay on as long as any power is supplied. Dont think the interior lights are exactly related but I do think that maybe its a sign of harness issues.
les_joey_paul: (2014-07-20 14:16:18)
What did you do to the car? Was everything working before?
drb5721: (2014-07-20 16:06:43)
This particular car was purchased through a friend who began a part out on the car. All harnesses that came with the car were the original harnesses. The car was purchased with the intent to build an engine for is since it did not come with that or a trans. Now that the engine is installed along with the trans, it is time to start the car. It turns over just fine. As of today I WAS able to get jolted by the coil when turning the key. However, its not something that happens consistently. I also test spark at the plug and noted that there is spark when the coil is working right.
New Distributor.
New Coil.
2 stock PTUs for diag
1 PRW2
New 255 fuel pump
New Plugs
New Cap
New Rotor
Good Wires.
All fuses good.
I have ohm'd out the coil and it is in spec. Have a second coil that is also in spec.
I have pulled the PTU harness through the fender to the cabin and test continuity throughout the whole harness to the ecu. Continuity does exist on each wire from ECU to corresponding component connector.
On BLUE coil wire there is about 8V. On GREEN coil wire is 12v.
At CAS harness connector there is 12v on the power pin.
Still getting codes 11 and 21 for CAS and Ignition Signal. However with spark not being consistent, that should cause and issue with the CAS, at least in my theoretical mindset. However, at the same time, this issue could also be CAS no good and not signaling for coil to fire. Not sure which way to approach this any more. I have tried 3 separate EFI harnesses. 4 Distributors. All 3 PTU's. I have 2 stock ECU's and 1 Nistune ECU. I cannot use the Nistune ECU for diag with the current EFI harness due to injector impedance differences from 87 ECUs to 88.
The only NOTABLE issues that are apparent with each harness is that the interior lights are ALWAYS on when power is supplied to system. I cannot get power to ecu with EFI relay in connector. I have to jump the BLACK wire and BROWN wire. I also cannot get the fuel pump to PRIME. It does pump fuel but does not turn off after 5 seconds. This leads me to believe I may have an issue in another harness but cannot verify that yet. But with continuity throughout the harnesses I feel I should be able to atleast get spark. The fuel pump issue has been documented, but have not found a solid fix. It is documented that I WILL NOT cause the car not to get spark. GE posted that I should check my fuel circuit for the answer. I have checked wiring, swapped relays and cannot get the pump to just prime. I also cannot hear injectors click when spinning dizzy by hand. I started with a known working Pathfinder dizzy as well as a known working Z dizzy. Had the Z dizzy replaced, no improvement, so had it replaced AGAIN, and no improvement. I really dont think I have 4 BAD distributors…
Maybe Ill try to grab up another PTU for the heck of it?
I have a spare car that I was driving and have pulled both engine bay harnesses, maybe my issues lie in the cabin harness and I should pull it as well?
C.Gesler: (2014-07-20 20:15:47)
As far as spark when you did the prw-2 swap Did you switch the Green/white wire with the black wire
For your fuel issue open up the ecu and see if it is burnt I had a similar problem and had a burnt fuel circuit
drb5721: (2014-07-20 21:16:36)
Yep. Wires were swapped. Seems like spark is there now. Fuel pump is definitely pumping. Still no starting.
les_joey_paul: (2014-07-21 01:32:43)
Is your distributor installed correctly? It will only work in one exact position when installed.
drb5721: (2014-07-21 02:11:40)
Something I noticed today in comparing engine bay harnesses is that the original harness has only 3 relays on the fusible link side. The green efi relay, black uphold relay, and the Orange safety relay. The one from my other car has a blue relay, uphold relay and what looks like a small control box. Could this make any huge difference?
Here are the differences, 1st harness being the one from my running car (which wont turn the starter over), second being the harness from this particular car.
Both harnesses offer the green and orange relays, however the first harness which show the group of 3 together, is not on the original harness.
Augustus Maximus: (2014-07-22 17:01:40)
There are differences in the harness from year to year. 84-85 harness has less relays. You should gives us more specifics about the car etc.
drb5721: (2014-07-22 17:25:10)
The car is an 87. Originally an automatic NA. Swapped in 5 speed trans, and built turbo engine. Have finally got spark from coil and its getting to the plugs. However, i am still getting codes for Ignition Signal. Fuel pump works but will not prime. ECU does not get power without crossing wires in efi relay.
C.Gesler: (2014-07-22 19:08:50)
Check ignition circuit from ign switch to efi relay
Augustus Maximus: (2014-07-22 19:31:09)
Check if all the other electrical systems work. All wiper functions including intermittent, light, defogger etc. Unplug the TCU and see if the interior light goes away. Check pins 107, 109, 112,113 for ground. Connect your DMM to the coil and check if it gets 12V from the ignition switch.
drb5721: (2014-07-22 23:33:00)
Will an 87 run on a harness from previous years?
Augustus Maximus: (2014-07-23 00:51:05)
Not earlier than 86
drb5721: (2014-07-23 01:06:58)
well I have to imagine the harness that was in the car was the factory harness meaning it was from an 87. The relays I show in the first picture make me think I need to make this harness work but I am unaware if there is gonna be a driveability difference between the two, depending on which one I can get to work. I will be checking for grounds on those pins shortly and will post back with results, but since these pins seem to be related to the FICD, would that be part of my issue? I have to figure out this ignition signal problem and fast. Tired of waiting to hear this thing run and all i have left is wiring problems.
Augustus Maximus: (2014-07-23 11:58:58)
I have a 87NA2T/AT2M along with a spare 87 and a 85 EFI harness, if you need pics or to compare voltages let me know. I have three running Z'z so verification shouldn't be difficult.
drb5721: (2014-07-23 12:27:59)
Well after swapping in the known working 87 engine harness, it wouldnt even turn over. I scanned over it and see some wiring issues in it so I swapped the original one back in. Turns over again, injectors pulse, but once again back to no spark. Will get the spark back this evening as ill have some daylight when I get home. I will probably need you to check your harness for comparisons as I move forward. Also going to check compression. Rings were installed according to factory procedure so dont think Ill have an issue there, but its not hard to check. Once I get spark from coil back, I will make sure I have spark at the plugs.
drb5721: (2014-07-24 01:46:08)
SPARK IS PRESENT AT BOTH COIL AND PLUG. Definitely have good spark too. I might even be sterile now. So I have spark, can smell fuel being emitted so now its down to air I am guessing. The engine does choke though like its getting too much fuel. The fuel lab regulator is set at base pressure which is in the 35-40 range i believe. Have to verify. It turns over good and smooth for a bit then gets to a point where its struggling, almost like its getting flooded, then kicks back to smooth turning for a bit. I am getting scared I have an issue with compression however. ANYTHING else I should look for before doing the compression test?
C.Gesler: (2014-07-24 02:05:11)
Pull plugs and smell them for fuel or oil, then do compression test. It dosent take to long and at least you can rule out an internal problem
you said it smells like it is getting fuel check for fuel in the fpr vacuum line, I've had one lockup an engine before
drb5721: (2014-07-24 02:19:54)
It is definitely getting fuel. That means I have 2 parts of the equation.....Air is the only thing left for it to attempt to run.
les_joey_paul: (2014-07-24 03:20:56)
You using iac?
drb5721: (2014-07-24 12:15:21)
i do NOT have IAC hooked up. Did not plan to use it with the pathy manifold. IDK the exact spec of compression but it does have compression, as you can tell when the engine is turning over. IDK what compression ratio the pistons are, will that change my results? I dont feel it has anything to do with compression though. I am gonna pull the injectors and make sure they are opening. I can hear them clicking when turning the key, but that doesnt mean they are opening fully or that all of them are opening. I am still getting codes 21 and now a 22. So also plan to once again search for an issue in the fuel pump circuit. It pumps fuel but wont turn off. just continuously runs.
les_joey_paul: (2014-07-24 13:50:47)
Check your fuel pump relay , and did you adjust your idle set screw at the throttlebody? Once you delete iac , you have to use that screw to hold the TB open a little, thus setting your own idle rpm.
drb5721: (2014-07-24 14:10:58)
Fuel pump relay does not change anything. I can completely remove the relay and pump still runs. I havent even got the car to run at all yet so I havent touched the BISS screw on the throttle body. I have however attempted to hold the throttle open while cranking and still no luck.
C.Gesler: (2014-07-24 14:11:12)
Dizzy was swaped 4 times make shure it isn't 180* out
drb5721: (2014-07-24 14:11:40)
Another note about the fuel pump is that as long as the fusible link is hooked up the pump will run. I do believe I have noticed it doing so even with ignition off.
drb5721: (2014-07-24 14:31:09)
I have re-checked the dizzy. Spark is definitely making it through to plugs so I'm not concerned too much about the spark at the moment. Now I need to figure out compression, and injectors are actually functioning properly.
les_joey_paul: (2014-07-24 15:45:00)
Sounds like fuel pump is shorted to ground.
Augustus Maximus: (2014-07-24 17:49:53)
If you manually rotate the pinion on the dizzy you will hear all the injectors clicking, once that is verified you can start looking at engine timing and/or ECU.
drb5721: (2014-07-24 18:58:44)
The injectors cycle when turning engine over. I'm gonna shoot a small spray of ether in to determine if it's fuel related
drb5721: (2014-07-26 01:27:28)
Codes are down to a 22. I have found that everything back to the fuse is good as when unhooking components prior to fuse it all stops the pump from running. Unplugging the fuse also does so. That makes me think I have a problem post fuse and between fuse and relay possibly? Does this sound right? If I unplug the blue relay the pump still runs. The pump runs regardless of key position so it's getting power at all times. The ecu turns off so it's not ecu related.
So I should inspect wiring between fuse and relay?
Augustus Maximus: (2014-07-26 03:46:33)
Unless you hardwired the pump, it shouldn't be running all the time. Time to swap ECU.
drb5721: (2014-07-26 13:08:15)
I do not think it is related to the ecu. Having swapped out 3 computers and having the same issue makes me think it has something to do with the wiring from fuse to the pump and more-so from fuse to relay. 2 of the computers have been known to work in my other z and the 3rd is a nistune ecu that was working with the Previous Owner. I plan to inspect the wiring from fuse panel to relay today and depending on what I find, relay to pump. Removing the underhood relay or fuse cuts power to pump. Removing in car relay does nothing meaning power is being passed through somehow.
drb5721: (2014-07-27 19:38:19)
I have revisited spark again as I found after an initial jolt there is not spark at the plugs. I originally confirmed spark after being shocked with the plug. I have since found out that I can get one spark out and then nothing else. New wires have been installed along with another new ignition rotor and a known good cap. Still cannot get spark. Charging battery for another go at it.
les_joey_paul: (2014-07-27 20:23:02)
Have you confirmed that the distributor rotor is pointing at the proper orientation relative to tdc of the crankshaft? I had a crank no start issue before and that's what the problem was. Insalled the distributor a few teeth off.
Also I'd verify your ignition coil.
drb5721: (2014-07-27 20:36:41)
I have a good spark from the coil to dizzy just nothing after. I have pulled the dizzy multiple times to check and adjust and no change.
Axel kain: (2014-07-28 15:48:58)
all you can do is swap the cap, rotor, and wires.... nothing else in the line to cause issue! ** make sure the rotor button's spring nipple in the cap is not broken off/stuck up in the cap!!!
drb5721: (2014-08-03 15:57:48)
Picked up another 87 this week. It's an NA with 154k. Fires up with battery being jumped since its dead. Bad brake light switch. However, it's a great candidate for diagnosis. Swapped dizzy cap transistor and all into this car and it fires right up. Gonna swap an ecu in and see what happens.
drb5721: (2014-08-03 16:40:21)
Swapped in ecus. One would not start the car at all. It's bad. The second one would start it but I ran like complete ass. Wouldn't idle above 400. Maybe now I'll run this known good ecu to the other car and see what happens.
drb5721: (2014-08-03 20:33:32)
Put known good ecu in car to see if it would start and there's a no go still. I'm down to thinking it's either internal engine or just an overall major wiring problem somewhere that I cannot find.
drb5721: (2014-08-10 23:10:35)
Harness from Augustus Maximus came from a running car. Swapped it in. Nothing. Car still will not start. I have put everything from dizzy to power transistor into this other z I have and it runs off these parts so there's nothing wrong with them.
I'm almost to the point of putting this engine in the other car and seeing what happens.
les_joey_paul: (2014-08-10 23:29:27)
Sounding like something mechanical now. Are you 100% that cam to crank timing is correct?
drb5721: (2014-08-10 23:49:06)
I have adjusted it multiple times. I have the driver cam spot on with timing dot. Have installed dizzy so it is pointing to 1 on the cap. Have pulled and adjusted a single tooth both ways a no change.
drb5721: (2014-08-11 02:22:19)
Readjusted dizzy one more time. Turned shaft 1 tooth back from where it pointed to the 1 on the cap. Fired right up. Next thing will be figuring out the fuel pump bc it continues to run as long as the fuse or fusible link are connected
les_joey_paul: (2014-08-11 02:39:31)
Check the harness to the relay
les_joey_paul: (2014-08-11 02:44:57)
Also do you hear the relay for the fuel pump click at all?
drb5721: (2014-08-11 02:59:47)
The relay has been swapped to see if it was bad. Same problem. It's done this will 4 ecus. I've attempted to ground the ground wire to the relay and nothing changed. Maybe an issue in the shielded wire? Relay does not click. Pump runs regardless of key on or off. If battery is hooked up, pump runs. It is a walbro 255 in tank.
les_joey_paul: (2014-08-11 07:17:40)
Did you do the hard ground mod? The Walbro draws more current than the stock pump and needs a constant 12v to run properly. It's possible a connector melted or something. You have a short to ground on the ground side of the circuit somewhere. The ecu ground side switches through the fuel pump relay. Then once it's switched, the ecu varies the voltage to the pump from 10 to 12v according to load. That's why you need to add the extra relay on the ground side of the circuit, having the ecu varying the voltage to the relay, while the switched side provides a path to ground. Doing this, the pump will always run at 12v when switched, and the ecu still thinks it's doing it's job and won't throw the fuel pump code.
Also this will probably fix your problem because your grounding it right next to the pump anyway.
drb5721: (2014-08-11 12:08:06)
I have not done the hard ground mod as it wont turn off at all if the fuse and link are connected. I have not found a melted connector and have traced all wiring from pump to relay. So all I can image is its between fuse and relay?
les_joey_paul: (2014-08-11 14:05:45)
Trace the ground back you the ecu. If it was a short on the power side, it would have blown the fuse. Are you using an ohm meter to trace? Also I suspect it could be a ground problem because your fuel pump relay isn't even clicking on
JSM: (2018-02-13 01:51:00)
Something I noticed today in comparing engine bay harnesses is that the original harness has only 3 relays on the fusible link side. The green efi relay, black uphold relay, and the Orange safety relay. The one from my other car has a blue relay, uphold relay and what looks like a small control box. Could this make any huge difference?
Here are the differences, 1st harness being the one from my running car (which wont turn the starter over), second being the harness from this particular car.
Both harnesses offer the green and orange relays, however the first harness which show the group of 3 together, is not on the original harness.
Can you tell me what the fuses off the safety relay are for? Are you bypassing power to it to get it to remain closed so the injectors are always getting power?